Field of the Invention
The present invention relates to a data storage device including a FLASH memory, and in particular it relates to executing the garbage-collection process on the FLASH memory.
Description of the Related Art
The garbage-collection (GC) process has been widely used on various kinds of memory devices. Specifically, the garbage-collection process is utilized to merge inefficient blocks where most of the pages are spare or empty into one efficient block for obtaining more spare blocks. Therefore, by regularly executing the garbage-collection process, the efficiency of the memory device could be improved.
However, whether the garbage-collection process is executed or not is usually determined by a single threshold value. When it is determined that the garbage-collection process is to be executed, the performance of the memory device suffers. For example, write latency suddenly increases and the performance abruptly decays due to the execution of the garbage-collection process. In addition, the memory device has different operation status and can be accessed with various commands from the host. Therefore, a dynamically adjusted garbage-collection process is needed to prevent the memory device of abrupt-decaying performance and also accord with various kinds of operation status and host commands.